1. Field of the Invention
This invention relates generally to a propulsion mechanism for use with float tubes, also known as belly boats, pontoon boats, and other floatation devices commonly used in fishing, duck hunting, and other aquatic pursuits and, more particularly, to a foot fin assembly for propelling the user of such devices while in the water. Specifically, the present invention relates to an improved foot fin assembly for use in propelling the user of a float tube or other similar floatation device in a forwardly facing direction while in the water while simultaneously permitting the user of such a foot fin assembly to walk in a forwardly facing direction in shallow water and on land without removing the fin assembly.
2. Description of the Prior Art
In general, users of float tubes and similar devices for fishing and other aquatic pursuits incorporate some type of propulsion devices on their feet to assist in moving about the water's surface. Most float tube fins presently used are similar in design to the foot fins used by swimmers and divers. Illustrations of such devices include those shown in U.S. Pat. No. 3,183,529, U.S. Pat. No. 4,857,024, U.S. Pat. No. 4,929,206, U.S. Pat. No. 4,940,437 and U.S. Pat. No. 5,597,336. Such devices operate by movement of the user's legs and feet in a flutter kick which propels an outstretched swimmer or diver in a forward direction. However, when such devices are utilized by a person seated in or on a float tube or similar device, they propel the user rearwardly or backwardly relative to the direction he or she is facing. This direction is generally opposite the direction the float tube user wishes to move when pursuing rising fish or in moving to another spot located in front of him or her. Moreover, the efficiency of such prior art fins is low so that the use of such devices when traveling any type of a distance in the water while using a float tube or similar device is generally very strenuous and tiring.
In addition, these types of fin devices limit normal walking foot movement due to their forward extending fin portions, which creates a risk of tripping and falling while walking with the fins on. Walking in marginal water to enter or exit a body of water is particularly hazardous, for in addition to the clumsiness of the protruding fins and the restriction of movement and visibility caused by the wearing of the float tube, the walker has to overcome the water's resistance on the fins with each step. As a consequence, most float tube users of forwardly extending fins walk backwards to enter and exit the water. While this procedure alleviates the protruding fin problem, such backward walking with a bulky float tube in place presents yet another problem since it creates a significant danger of falling and injury to the float tube user.
The process of donning and removing a float tube while wearing such forwardly extending prior art fins is also difficult and hazardous. For example, the bulk and shape of a donut shaped float tube surrounding a user's body limits a user's movement, necessitating that the fins are attached to the user's feet prior to donning the float tube. In such an instance, with the float tube lying flat on the ground and the fins attached to the user's feet, the user balances on one foot while stepping over the circumference of the tube with the other foot to insert that foot with fin into the leg opening of the float tube seat. Thus straddling the tube, the user then shifts his or her balance to the foot now inside the tube so as to lift the opposite foot with fin over the tube and insert it also into the leg opening of the seat. At this particular point, balancing is especially difficult presenting a danger of falling. The forward extension of such prior art fins, their general configuration and size, and the constriction of the seat of an annular float tube make it extremely awkward to insert both feet with fins in place into the leg opening of a float tube. Balancing is especially difficult while bending over to maneuver the unwieldy tube into position to facilitate inserting the forward extending fin of the second foot into the leg opening.
As the result of such difficulties, several fin structures have been designed to provide a means of forward propulsion by float tube users. Moreover, designs have been provided wherein a single paddle is secured to an existing shoe of a float tube user. Such designs include U.S. Pat. No. 2,395,844, U.S. Pat. No. 4,664,639 and U.S. Pat. No. 5,527,196. Other designs such as U.S. Pat. No. 2,276,082 and U.S. Pat. No. 3,432,868 have provided elongated or funnel shaped fins attached to the outside sides of the legs of a float tube user as an integral part of wading boots or waterproof garments for float fishing. An unpatented device known as the Paddle Pusher by Fishmaster Manufacturing Co. of Oklahoma City, Okla., provides side paddles to be worn on existing tennis shoes or other footgear. The design of these types of fins compel the float tube user to assume a forced, unnatural position in the float tube during use. Moreover, these designs are generally inefficient, lacking the advantage of a longer arc of leg movement in the water which can be gained only by positioning the fin in an operating position underneath the foot of a user. They also lack the advantage of a fin biased to an operating position from which the fin will generate usable thrust more rapidly than a fin which must be initially extended to its operating position by movement through the water.
The design and construction of a float tube seat typically places a user thereof in the posture of a person seated in a chair with his or her legs and feet extended generally outwardly and forwardly. In such a position the kick is restricted to lower leg movements with the legs pivoting at the knees, not at the hips as is assumed in many prior art swim fin-like devices. Use of the fin disclosed in U.S. Pat. No. 4,664,639 in which the fin is integrally secured as part of the sole of the shoe or as part of a sleeve that fits over the shoe requires the user to lean forward against the designed posture of the float tube in order to position his or her body and legs in a generally upright vertical plane to provide a sufficient length of kick to make adequate use of the device. This is due to the fact that the integral fin flap of this device is by its nature biased toward its retracted position against the boot sole necessitating unusual motion and force from the leg and foot of the float tube user to extend the fin away from the sole of the shoe and into position to create forward user motion.
The devices of U.S. Pat. No. 2,276,082 and U.S. Pat. No. 3,432,868 and the above described Paddle Pusher also compel the user of a float tube to assume a forced, generally upright vertical position to move through the water. As a consequence of such designs, much of the user's leg motion with these devices is wasted, and such awkward movement within the float tube is inherently uncomfortable and dangerous. Moreover, a forward propulsion fin device known as Float Striders (patent pending) by R.C. Enterprises, Ghent, N.Y., provides a coated fabric into which tubular ribs are sewn to stabilize the fabric in a generally planar fin-type surface. This device attaches loosely downwardly and behind the heel of the user's foot, being secured to the user's boot by woven straps and buckles. In walking to enter and exit the water, the fin surface of this device drags on the ground behind the user's foot, thereby creating a danger of tripping and falling if the user of the device were to be in a rearward, off-balance position. In use in the water, this fin device loosely depends downwardly from its attaching straps. Consequently, the device is inefficient in that it is not biased in an operating position other than by the forces of gravity. Moreover, many users of float tube fins do not wear boots, preferring to eliminate the weight of the boot by using only "stocking foot" waders. If used over stocking foot waders, the Float Strider device tends to slip off the foot since there is no protruding boot heel about which the fin and its webbing straps are retained.
The devices of my above-incorporated U.S. Pat. No. 5,531,621 and U.S. Pat. No. 5,645,460 overcome many of the objections to the prior art devices raised above. However, the hinging arrangement and means of extending the fins of these inventions can sometimes be a little awkward when moving them from a closed to an operative position. Both devices are also rather complicated. The devices of my above related and incorporated U.S. Pat. No. 5,593,333, improves the ease by which a user can move the fin assembly device from its reset position for minimum water resistance to its operative position for paddling or to its fixed position for walking in shallow water. However, the hinging mechanism and bias structure for this device are heavy and somewhat expensive to manufacture. Maintaining free movement of the hinging mechanism also requires special lubricant impregnated bushings, while salt-water use presents a corrosion problem due to electrolytic activity of dissimilar metals generally used in the spring and hinge. Consequently, there is still a need for a fin assembly for use by float tube users which is efficient to use, easy to walk on, easy to wear when donning a float tube, and simple and inexpensive to manufacture.